You board the plane, get used to the smell of stale sick, and sit down, awkwardly jiggling your knee around the hair’s width of space that exists between your leg and the seat in front. Take-off goes smoothly so your eyes fixate on the seatbelt sign. Finally it fades out, and you push the button to recline but — disaster. The anoraked bloke behind you has fitted a Knee Defender — the £13 clip that stops your seat from moving at all. The outbreak of war at 30,000 feet seems inevitable.

Or so suggests the evidence of the past few weeks. One passenger hurled a glass of water at one such Knee Defender-user on a United Airlines flight last month, while a similar row on an American Airlines flight to Paris saw the jet diverted after two passengers came to blows: air marshals on board intervened, and one passenger was arrested on landing.

That’s clearly bad behaviour, but the booming business traveller market is a complicated place. London’s airports are the world’s busiest hubs for flying suits and now even Ryanair wants a piece of the market, this week starting to sell frills to business people (fast-track security, priority-boarding seats near the exits for a £59.99 fee) after noticing rival easyJet had lured 10 million business passengers to its planes every year.

You can spot the business traveller at the airport: among other habits, they’re wheeling a tiny black carry-on (about the same size as the bag I use for my on-board chocolate stash), and easing through security.

Here, some of London’s most frequent flyers reveal the rest of modern-day jetiquette.

Behave as you would on land

If you’re bringing your own food on board, “a sandwich is fine, a smorgasbord of rancid marine life is not,” moans one frequent flyer on an aviation-geek noticeboard. But that’s not the worst of mile-high behaviour.

“Some flyers whip off their shoes immediately, then drape their socks on the armrest,” reports Tom Otley, who flies long-haul every other week as editor of Business Traveller magazine. “It’s not pleasant — you’ve got to share that small space with them for 10 or 12 hours. Then there are those on board who break wind for the first four or five hours of the flight. Ugh — it’s not like you can get up and go anywhere.”

Treat other passengers as you would Tube travellers, adds Otley, who’s flying to Moscow, Beijing, Hamburg, Doha, Washington, Istanbul, Hong Kong and Mumbai in the next month. “If you fly regularly you tend not to chat with people — either you’re working or you’re tired and want to go to sleep. It’s not rude to forgo small talk.”

If your neighbour does insist on chit-chat, “put on your headphones and make a performance of taking them off each time they interrupt you” is the advice of Niall McBain, who takes three international flights a month as chief executive of content agency Spafax.

Oh, and the air stewards aren’t making eyes at you: they’ve heard it all before and just want to do their jobs in peace.

Pick your seat with care

When ex-BP boss Lord Browne downgraded himself to commercial flights he always demanded British Airways’ first-class seat 1A, his former lover Jeff Chevalier famously revealed. But cabins have moved on, according to management consultant Andrew Solum, who works in Canary Wharf but takes two or three flights a week.

Speaking to me from Nice, before he flies back to London then over to Penang in Malaysia and on to New York (“You know it’s bad when immigration officers and check-in staff not only know your name, but ask how your parents and family are doing,” he says), Solum says: “I’m very religious about my seat — but on BA’s 747s. I like 3A or 3K — they’re the ones with the most amount of real estate in the cabin. The upper desk is best, it’s like flying on a boutique private jet, and whatever the class you never want to be too close to a galley or lavatory, which are noisy. I always prefer a window seat, because there’s nothing worse than someone banging into your seat with a trolley or cabin bag. Sleep is critical.”

For shorter flights the top tip is row four: it’s where the cabin crew start serving food and drink.

Ardent flight-nerds go even deeper with their research, combing the thousands of plane seat reviews (seriously) on sites like Seatplans.com.

The private set

If it’s a private jet you’re boarding, there’s a whole different rulebook. “Always let your host board the aircraft first,” says Adam Twidell, chief executive of broking site PrivateFly. “He or she will have a favourite seat, and you don’t want to make this your first and last invitation. Be demanding — operators are used to being asked for specific music, magazines, herbal teas, or organic dog food — and talk to your pilots. There’s no locked cockpit and the crew will welcome you to the flight deck,” says Twidell.

“Disappear quickly — the point of private jet travel is to be whisked away from the aircraft steps. If you forgot to arrange a car, ask your pilot to radio ahead and order a taxi. And don’t carry your own bags — it’s not expected and that’s what the ground crew are for.”

But don’t expect the whole trip to be über-luxurious: sometimes the loo is just a lidded seat behind a curtain. “Everyone knows when you go in, and it’s not, uh, sound-proof,” one PJ flyer blushes. Plus some very light jets don’t have a toilet at all, so you might want to use the terminal’s.

Surviving the red-eye

Get on board, change your watch to your destination’s time zone and try to go to sleep. “I can’t believe the number of people I see stuffing their face or watching a film on the JFK to Heathrow red-eye,” says one who flies it weekly. “Waste of time. The maximum shuteye you’ll get is six hours, so eat at the airport — airline food is terrible, wherever you’re sitting — then go to sleep on board.”

Or you could always try to upgrade yourself. “On a flight from Russia to Mongolia we were travelling in economy but waited at the gate until everyone had boarded. As we entered the plane we slipped into the remaining business-class seats. The cabin crew was too distracted to notice,” admits McBain.

At the airport

Former MP Mark Oaten, who now runs trade body the International Fur Federation and takes 100 flights a year, has a strategy for beating airport queues. “Never get behind a pram or rucksack in the security queue,” he says, “but when entering passport control, do get behind a family as they never get stopped. Try to get two passports — one will always be waiting for a visa, and the Home Office will agree to this if you travel lots.”

However you’re travelling you’re still going to have to go through the scanner. “Don’t be part of the problem,” says Otley. “I see people queue at security for 10 minutes then look completely shocked when they have to take their belt off and laptop out. Oh, and don’t wear complicated boots with buckles — you know you’ve got to take them off, just wear slip-ons.”

Solum agrees: “The other day, going through Heathrow’s Terminal 5, a lady in front of me was wearing 17 bangles on her wrist. Each one was wedged on and she kept going through the machine, pinging, then having to take the next one off. It was five in the morning.”